Some of my family and friends bring their XR4s with stock jetting (good for sea level) up from the valley. Bikes run rich, but run OK at 7000'.
For 7000' riding, with no snorkel, K&N and a pipe, I'm running a 155 main, 55 pilot and a dual-taper needle in the middle position. Works well up to 10,000'.
I tried a 145 and didn't notice any "popping" at high RPM, but I think I was running very high head temps, since I noticed my head gasket "seeping", which went away when I jetted richer.
I used the correction factors from the manual to arrive at my current jetting. I know "leaner is meaner", but the XR doesn't seem to exhibit "tell-tale" lean pops/hesitation when jetted too lean, like I've experienced on too lean DRs.